Intake silencer



March 7, 1939. B 3 BROWN 2,149,836

INTAKE SILENCER Filed Nov. 4, 1935 2 Sheets-Sheet 1 W i- 1a March 7, 1939.

B G. BROWN INTAKE S ILENCER Filed Nov. 4, 1935 2 Sheets-Sheet 2 Patented Mar. 7, 1939 UNITED STATES PATENT OFFICE INTAKE. SILENCER Application November 4, 1935, Serial No. 48,128

3 Claims.

This invention relates to silencers of the resonator type in which the main duct consists of two telescopically related, radially spaced tubular members through whose interspace a chamher or a series of chambers which surround the duct are connected to it.

The invention resides in a modification of the passage which connects the duct with the chamber or series of chambers which makes it possible to reduce the length of the silencer without unfavorably affecting its silencing characteristics.

For a better understanding of the nature and objects of this invention, reference is made to the following specification wherein there are described the embodiments of the invention which are illustrated in the accompanying drawings.

In the accompanying drawings:

Figure 1 shows, partly in elevation and partly in section, an air cleaner and silencer assembly in whose silencer element there is incorporated one embodiment of this invention.

Figure 2 is a section taken on the line 2-2 of Figure 1 with parts broken away and in section.

Figure 3 shows, partly in elevation and partly in section, an air cleaner and silencer assembly in whose silencer element there is incorporated another embodiment of this invention.

Figure 4 is a section taken on the line i4 of Figure 3.

The silencer element of the assembly shown in Figures 1 and 2 includes a cylindrical wall I ll and upper and lower end walls II and i2 which are suitably connected to the wall ill. Through the center of the cylindrical element formed by the walls Ill, I I and I2, there extends a duct which consists of telescopically related tubes l4 and i5. The tube I4 extends through an opening in and is secured ,to the lower wall l2 and its upper end terminates short of, but near the upper wall ii. The tube l5 extends through an opening in and is secured to the upper wall I l It is coaxial with and of smaller diameter than the tube i4 and projects into the latter to about the level of the lower wall I2. The compartment defined by the duct i l-l5 and the walls i0, H and I2 is divided into two chambers I! and H! by a partition l9 through which extends a tube 20.

The cleaner element of the assembly forms no part of this invention and it is, consequently, unnecessary to describe it in detail. Briefly, it consists of a cup-like member 21 with a stepped bottom which when in operation is filled with oil to about the level indicated by the reference character O. A tube 22 extends through a central opening in and is secured to the bottom of the cup 2|. The tube 22 supports a filter element which consists of an annular receptacle 23 which is somewhat smaller in diameter than the cuplike member 2| and whose outer wall extends up- 5 wardly beyond the side wall of the member 2| and defines with it an air intake opening 21. The receptacle 23 has openings 24 and 25 in its upper and lower walls and is filled with a suitable filtering medium 26. The outer wall of the filter ele- 10 ment supports a cover 28 which closes the upper ends of the filter element and the tube 22 but is shaped so that air can flow from the upper end of the filter element into the tube.

Because the bottom of the cleaner element is 15 stepped, to form av compact assembly of the cleaner and silencer elements, the top of the silencer element is made concave. Because the top of the silencer element is concave, the duct 14-15 of the silencer element is shorter than it would be if the top were approximately flat, as it has been in previous designs. Shortening the duct Hl 5 naturally reduces the extent to which the tubes i l and i5 overlap and, therefore, increases the acoustical conductivity of the an- 25 nular passage I3 which connects the duct with the chamber I'l beyond that which it would be if the top II were fiat. To compensate for this, there is secured to the upper wall l l of the silencer element a ring-like member 29 which surrounds and is radially spaced from the upper end of the tube I E. The provision of the member 29, in efiect, increases the length of the annular passage l3 and permits the acoustical conductivity of the passage to be reduced to the desired value and, consequently, the operation of the silencer to be improved.

The cleaner and silencer elements are assembled as shown in the drawing with the lower end of the cleaner element interfitting with the upper 40 end of the silencer element and supported therefrom through a gasket 30. The'cover 28 is secured to the cleaner element and the cleaner element is secured to the silencer element by a yoke 3| and a thumb screw 32.

The cleaner element of the assembly shown in Figures 3 and ediffers materially from that shown in Figures 1 and 2 only in the inclusion of the perforated baffle 33. The silencer element of the assembly shown in Figures 3' and 4 differs materially from that shown in Figures 1 and 2 only in the provision of a ring-like element 34 which is secured to the partition i9 around and in spaced relation to the lower end of the ring-like member 29. The provision of the member 34 in efiect still further increases the length and reduces the acoustical conductivity of the passage l3 and permits the length of the silencer element to be further reduced without unfavorably afi'ecting its silencing characteristics. understood that additional elements, such as 29 and 3 3 which in effect would further lengthen the passage 53, provide additional turns therein and decrease its acoustical conductivity, may be employed if they are found desirable.

The cleaner and silencer assemblies shown in the drawing were designed for use in connection with the carburetor of an internal combustion engine to clean the air entering it and eliminate the noises ordinarily emitted from it. These assemblies are designed to be installed on a carburetor by connecting the tube M to the air intake pipe of the carburetor.

When one of these assemblies is installed as indicated, and the engine on which it is installed is operating, air is drawn into the opening 2'! and follows the path indicated by the arrows into the tube 22. During its passage from the opening 2'? to the tube 22, the air is freed of foreign matter. From the tube 22, the air is drawn through the duct lt-l5 to the carburetor.

The silencer element is, of course, so tuned that is the acoustical conductivity of the passages which connect the duct it-lS with the chamber ii and interconnect the chambers i1 and I8 and the volumes of the chambers H and i8 are so adjustedin the manner described in the Wilson application Serial No. 470,700, filed July 25, 1930, that it will prevent noises emitted by the carburetor from reaching the atmosphere. It will, I think, be understood from what I have said that this invention facilitates the proper tuning of resonator silencers of the type under consideration.

I claim:

1. In a silencer, a duct through which sound waves may travel, the duct including two telescopically related, radially spaced tubular elements, a. wall which encircles and is radially spaced from theduct, walls which with the tubular elements and the first-specified wall define a compartment which communicates with the duct through the aperture between the tubular .elements, and an annular element which is connected to the same of the second-specified walls It will, of course, be

outer of the tubular elements so that it defines therewith an angularly disposed extension of the aperture through which the compartment communicates with the duct.

2. In a silencer, a duct through which sound waves may travel, the duct including two telecommunicates with the duct through the aperture between the tubular elements, and annular elements which are connected, respectively, to the same of the second-specified walls as the inner of the tubular elements and encircles and is radially spaced from the inner end of the outer of the tubular elements and to the other of the secondspecified walls and encircles and is radially spaced from the inner end of the other of the mentioned annular elements so that they define with the outer of the tubular elements and each other angularly disposed extensions of the aperture through which the compartment communicates with the duct.

3. In a silencer, a duct in which there are included two telescopically related, radially spaced tubular elements through which sound waves may travel, a resonator which is arranged as a branch of the duct and includes a wall which encircles and is radially spaced from the duct and walls which with the tubular elements and the firstspecified wall define a compartment which communicates with the duct through the aperture between the tubular elements, a wall which subdivides the compartment lengthwise into two chambers, an aperture through which the chambers communicate with each other, and annular elements which are connected, respectively, to the same of the second-specified walls as the inner of the tubular elements and encircles and is radially spaced from the inner end of the outer of the tubular elements and to the third-specified wall and encircles and is radially spaced from the inner end of the other of the annular elements so that they define with the outer of the tubular elements and each other angularly disposed extensions of the aperture through which the compartment communicates with the duct.

BENJAMIN GRA'I'Z BROWN. 

